The value of resistance r was determined by measuring current I flowing through the resistance with an error e1=1.5% and power loss p in it with an error e2=1.0%. Determine the maximum possible relative error to be expected on measuring resistance r calculated from the formula r=p/I×I

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.